I just bought a 2007 Ram 1500 that has 45000 miles on it. 2wd, 4.7l, quad cab, flex fuel. Truck ran fine for 700 miles, then I started hearing a ratcheting noise when I would crank the truck up and go from park to reverse. I crawled under it and it sounds like some kind of solenoid trying to engage, but it can't for some reason. Also, it only happens when the transmission is warm and idling fast. If you let the idle go down to about 700rpm, it doesn't make any noise. Only when it idles above 1000rpm does it happen. I have read several posts similar to this, but nobody seems to have an answer. I took it to a Dodge dealer and couldn't get anyone who knew what I was talking about. Took it to a transmission shop and the guy said that all later model Chryslers did this.
Another question - should the truck be idling that high after it is warm. It doesn't seem to matter how warm the engine is. When it fires off, it starts at about 1200rpm, then after 15 seconds it gradually starts to creep down to about 650rpm. I don't understand why it has to idle that high if it is hot. I did reset the PCM using the 31st fuse method and I unhooked the battery for about a half hour just for kicks.
About the only other issue with the truck is that it downshifts from 4th to 3rd very firmly. So firmly that it is almost a clunk. After I reset the PCM, this problem appeared to be resolved, but now it is back. Also, it would hold onto a shift longer when accelerating after I reset it. These two symptoms seem to go hand in hand.
Transmission fluid is full and very clean. Truck runs very smooth and tight. Any help on this would be greatly appreciated.